Dialkyl monochloromethanephosphonate esters containing from 3 to 10 carbon atoms in the hydrocarbon radicals



United StatesPatent O 1 2,841,604 DIALKYL MONOCHLOROMETHANEPHOSPHO- NATEESTERS CONTAINMYG FROM 3 T0. 10 CARBON ATOMS. IN THE HYDROCARBON RADICALArthur-Dock [Eon Toy, ParkForest, and KennetliH.

- Rattenhury, Chicago Heights, 111., assignors to Victor Chemicallvorks,acorporation of Illinois No Drawing. Application August 23, 1954 SerialN 0. 458,004

5 Claims. ((31. 250-461) This invention relates todialkylmonochloromethanephosphonate esterscontaining from 3 to carbon atomstame hydrocarbon radicals.

" The plasticizers. commonly available normally are of little or novalue at low. temperatures. There is an increasing demand for civilianand military purposes for suchlow temperature plasticizers, particularlyfor use in artificial leathers for garments, seat covers for trucks, andother items. which must remain flexible at low temperatures.

The plasticizing agents of this application likewise are of particularvalue in their ability to impart flameresistant. characteristics to theplasticized resin products. This characteristic varies somewhat with thetype of resin employed. For example, excellent flame resistance isobtainediwith Vinylite, cellulose acetate and' ethyl cellulose, whereaswith nitrocellulose very little increase in flame resistance is obtainedthough an excellent low tem- ..perature plasticization is efiected.

In, the preparation of the new plasticizingcompounds,

it is, first neces sary to prepare, by known, means, the.monochloromethanephosphonic dichloride, and then react hexanol (1.2moles+2( ]0% excess). The system was evacuated to 20 mm. pressure and100.5 grams of monochloromethanephosphonic dichloride (0.6 mole) addeddropwise while maintaining the temperature between 25 and 30 C.Theaddition took one hour and eleven minutes. The flask was then pumpedat 20 mm. pressure for 2 hours at 25-30 C., 15 minutes at 35 C., 15minutes at C, and 15 minutes at C. The pressure was reduced'to 4 mm. andthe heating continued for one and one-half hours to substantially removeall of the liberated hydrogen chloride. The solution was thentransferred to a distillation unit and the excess 2-ethyl hexanoldistilled oif at 3 mm. pressure and 5363 C. The crude product was washedwith 300 ml. of 5% NaHCO solution and the organic layer separated anddistilled at to 163 C. at 1 mm. pressure yielding 189.4 grams (93.5%yield) of di(2-ethylhexyl) monochloromethanephosphonate. Theesterproduct had an index of refraction N =L4505 and an acidity equal to 0.35ml. of 0.1 N NaOH per 10 grams.

In another example dipropyl chloromethanephosphonatewas made by reactingn-propanol and chloromethanephosphonic dichloride using triethylamine asa hydrogen chloride: acceptor, as follows:

In athree-neckedS liter flask was placed 315.0 grams of n-propanol; (5.0moles plus 5% excess), 530.2 grams of t'riethylamirie (5.0 moles plug 5%excess) and 2 liters of benzene; The solution was cooled to 0.0 C. and419 gram (2.5,fmoles) of monochloromethanephosphonic dichloride addeddropwisewith stirring at 05 C. over a 2 hour and 50 minute period. Theslurry was stirred for one hour at 05; C. and-allowed to stand overnight. The slurry was then filtered to remove the amine hydrochlorideand the cake washed with 900 ml. of benzene. The filtrate was placed ina 5 liter distillation unit and the volatiles stripped off at 50 C. and1 mm. pressure. The liquid product. was then distilled at a vaportemperature ot'7890 C. at 1 mm. pressure yielding 435.0 grams (81.4%yield) of di-n-propyl monochloromethane- 'phosphonate having an index ofrefraction N =1.4395.

In a similar manner other dialkyl monochloromethanephosphonates wereprepared having the properties shown in the following Table I.

Table I Monochloromethanephosphonates Dipropyl Dibutyl Diamyl DihexylDi-iso-- Di (2eth- Dinonyl Didecyl octyl ylhexyl) Boiling point, C 72-82101 122-130 124-138 155 201 Press, mm 1.0 1.' 1;0+2.0 2.0 1.0 1.0 1.01.0 Refractive index Ni)- 1. 4395 1-. 4418 1. 4443 1. 4462 1. 4609 1.4509 1. 4570 1. 4545 Acidity, ml; Ab- N NaOH/gm 0.02 1 0.03 0.01. 0.010.01 0.06 0. 03 0.03 001 l 12.8 11.5 10.4 8.7 8. 7 8.1 '7. 5 Percent CL.16. 5 14. 7 13.1 11.9 10. 0 10. 0 9. 2 8. 5 Thermal stability, perv centdecomposed 2. 78 2. 21 3. 55 Hydrolytic stability, percent decomposed10.0 2. 8,, 0.12

Volatility, percent weight loss 0.7 0.2 0.1 Freezing P t, 0 8 (0 Flashpoint:

Open Closed e (0 Viscosity, cp. 30 C 12 .16 19 Surface tension, Dynes/cm. at 30 0 26. 0 27. 3.. 27. 5 28. 1

! Water=white.

7 Viscous liquid at 70. 3 Over 250 F.

4 Over 860 F.

The data on thermal stability in the above Table I were determined byplacing a weighed amount of the ester in a 3-necked flask equipped withstirrer and thermometer and heating at l45-150 C. for 24 hours. Theincreased acidity as determined by titration with l N caustic soda wasused to calculate the percentage of ester decomposition.

Hydrolytic stability was determined by refluxing a mixture of 100 ml.water and 20 grams of the ester for a period of 24 hours, cooling andtitrating the aqueous phase with /3 N caustic soda to determinedeveloped acidity which was then calculated as percentage of esterdecomposition.

Volatility was determined by heating the ester in a flask with stirringat l45l50 C. for 24 hours and determining the percentage weight loss.

The above ester compounds are soluble in methanol, ethanol, acetone,methyl acetate, benzene, hexane and carbon tetrachloride, but insolublein water.

All of the above described esters have been found to be excellent lowtemperature plasticizers for Vinylite resin films and impart excellentflame-resistant character to the Vinylite resin films.

The propyl to hexyl species of the above esters have excellent lowtemperature plasticizing and flame retardant characteristics withcellulose acetate resin films.

All of the above esters are excellent low temperature plasticizers forethyl cellulose and nitrocellulose resin films but do not greatlyenhance the flame eflect on such 'resin films.

The low volatility, high thermal stability and low temperature fluidityof the above esters make them highly suitable for use as hydraulicfluids, particularly under low temperature conditions.

The following data illustrates the fluidity of the esters shown therein:

The viscosity indexes shown were calculated from the above viscositydata by the method described in ASTM Standard QD 151, Am S3, l9535, p.88.

Plasticized resin products may be produced by intimately mixing with thedesired resin material a plasticizing proportion of themonochloromethanephosphomate, with or without the aid of suitablesolvents. In general, it has been found that desirable plasticizingeflects may be obtained where the proportion of the plasticizing esteris within the range of 20 to 40 parts by weight per 100 parts of theresin to be plasticized. Such plasticized products are suitable for useas molding compounds or in the form of films or coatings in a variety ofcommercial applications.

Evaluation of the new monochloromethanephosphonates as plasticizers wasmade by dissolving the resin and plasticizer compound in a suitablemutual solvent, casting .films therefrom of uniform thickness andevaporating off the solvents to obtain dry plastic films. Films weremade using V inylite (a copolymer of 80-95% vinyl chloride and 20-5vinyl acetate), ethyl cellulose, cellulose acetate and nitrocelluloseand several plasticizing proportions of the various dialkylmonochloromethanephosphonates. the plasticizer and determine thecharacteristics of the plasticized resin products. Some typical examplesare shown in Table II.

The films were then tested to evaluate 'phate, a well known plasticizerof the prior art.

Film clarity is determined by visual observation, and is a measure ofthe compatibility of the resin and the plasticizer. Cloudiness in thefilm is an indication of incompatibility and is an undesirablecharacteristic though it does not necessarily mean that no plasticizingeffect is present.

Exudate is a term used to designate the presence of exuded plasticizeron the surface of the plasticized resin film. Its presence or absence isdetermined by rubbing a cigarette paper over the surface of the film(previously dried for 4 hours at 80 C.) and noting Whether or not thepaper shows any absorption of the plasticizer. The test is a measure ofcompatibility not observable by the visual clarity of film test. Theexamples reported in Table II show that in all cases the newplasticizing agents are compatible with resins tested.

Flammability of the plasticized resin films was determined by holding aflame at the bottom of a verticallyhung film (approx. 0.03 inch thick)for several seconds, then removing the flame. If the film continued toburn, it was designated as flammable. If the flame is immediatelyextinguished, it is designated self-extinguishing. If the film chars ormelts without flaming except during the application of the flame source,it is said to be non-flammable. From the examples shown in Table II, thenew esters are excellent plasticizers for Vinylite, cellulose acetate,nitrocellulose and ethyl cellulose resins, but the additional advantageof increased flame-resistance is of considerable importance only inconnection with the Vinylite and cellulose acetate resins.

Moduli of rigidity as reported for some of the plastic films in Table IIrepresent a quantitative measure of the flexibility of the films at atemperature of about minus C. The lower the figure reported, the moredesirable and more flexible is the film at the low temperature. Thus,for example, the preferred plasticizers for Vinylite film are within thegroup ranging from dibutyl to dioctyl monochloromethanephosphonates.However, all of the ester compounds ranging from the dipropyl to didecylesters are highly satisfactory low temperature plasticizers whencompared to the plasticizing effect of tricresyl phos- The modulus ofrigidity test was made using a modification of the procedure andapparatus described in the paper Measurement of Flexibility of LacquerFilms (Products Finishing, May 1952). The procedure consists ofsuspending a uniform strip of the plastic film from a torque calibratedwire with a definite weight attached to the ing. At the top of theapparatus is a calibrated rotation element attached to the torquecalibrated wire. From the torque measurement when the film strip istwisted through a angle the modulus of rigidity is calculated from theformula by St. Venant (British Air Ministry Specifications) TL cd abwhere, G is the modulus of rigidity in dynes/cmfi; where T=appliedtorque in dynes/cm.; L=length of film strip, cm.; C=width, cm.;d=thickness, cm.; b=angle of twist, radians; and a=constant 0.313 forflat strip shape.

The testing apparatus is placed in a vessel maintained at the desiredtemperature while conducting the tests. In the present examples, thetemperature was held at minus 50 C.i-1. The film thickness was 0.035inchi0.0003 and the width 0.25 inch:0.004.

Qualitative low temperature flexibility tests having goodcorrelation'with the above tests were made on films of Table II byimmersing film specimens in a vessel at minus 50 C. and bending thefilms with tongs a number of times. All of the plastic film of Table IItested showed good to excellent flexibility at minus 50 C.

Table II Resin Plasticizer Solvent vFilm clarity Flexibility at EFlammability Moduli of rigidity Vlnylite (copolymer of 95% vinylchloride and 5% vinyl acetate).

Cellulose acetate...

Nitrocellulose Dipropyl monochloromethane I phosphonate.

lIIIIdo--- Dibutyl monoohloromethanephisphonate. o

Di(2rethylhexyl) monochlororngthanephosphonate.

Diisooctyl monoohloromethanephosphonate. v

Dinonyl monochloromethanephosphonate.

Didecyl monochloromethanephosphonate.

Tricresyl phosphate Dipropyl monochloromethanephisphonate.

Dibutyl monochloromethanephosphonate.

Diainyl monochloromethanephosphonate.

Dihexyl monochloroinethanephosphonate.

Diisooctyl monochloromethanephosphonate.

Di(2-ethy] hexyl) monochloromethanephosphonate.

Tricresyl phosphate Dipropyl monochloromethane- Methylethyl ket one.

one,

81. cloudy--.

Cloudy.

White ppt... Clear E xcellent Good Self extinguish- Flammable- Nonflammable. Flammablephosphonate.

.-...do do Dibutyl monochloromethanephosphonate. ..do d0 Diisooctylmonochlorornethanephosphonate. Di(?rethy1hexyl)monochloromethanephosphonate. Tricresyl phosphate Dipropylmonochloromethaneplgisphonate. o

Ethyl cellulose.

-do Dibutyl monochloromethanephosphonate. do

Diisooctyl monochloromethanephosphonate.

butyl acetate, toluene, and ethanol.

-do Mixture of ethanol and toluene.

Di(2-ethy] hexyl) monochloromethanephosphonate. Trieresyl phosphateNote.-The dashes indicate instances where no determination was made.

General plasticity of the plasticized films at room temperature weredetermined organoleptically by at least three observers and all of thefilms plasticized with the new esters were rated as having good toexcellent plasticity.

It will be noted from the foregoing tables and discussion that all ofthe compounds having from 3 to 10 carbon atoms in the hydrocarbonradical have considerable value for the purposes disclosed. Thecompounds with 4 to 8 carbon atoms in the hydrocarbon radical, however,have improved values for some of the purposes described.

The foregoing detailed description has been given for clearness ofunderstanding only and no unnecessary limitations should be understoodthereform as modifications will be obvious to those skilled in the art.

We claim:

1. A water-insoluble dialkyl monochloromethanephosphonate of the formula\P RO OHICI References Cited in the file of this patent UNITED STATESPATENTS 2,550,651 Dickey et a1. Apr. 24, 1951 2,573,568 Harman et a1.Oct. 30, 1951 I (Other references on following page) 7 8 UNITED STATESPATENTS FOREIGN PATENTS 2,694,689 Gamrath et a1. Nov. 16, 1954 7 603,840France Apr. 23, 1926 2,708,204 Bell et a1. May 10, 1955 2,714,100 Toy eta1. July 26, 1955 QTHER 2 725 311 Kenaga et 1 Nov. 29 1955 6 Elhs:Chem1stry of Synthenc Resms, v01. 1, page 2,787,629 Coover et a1. Apr.2, 1957 13 T-Iabachnik: 46 Chem. Ab. 4210 1952 Patent No... 2,841,604July 1, 1958 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTIONArthur Dock Fon Toy 'et ala It is hereby certified that error appears inthe printed specification of the above numbered patent requiringcorrection and that the said Letters Patent should read as correctedbelow.

001mm 2, line 26, for "plug read plus line 28, for "gram" read gramscolumns 5 and 6, Table II, the term Nitrocellulose" appear ing under theheading "Resin" should be lowered one line,

Signed and sealed this 9th day of December 1958.,

(SEAL) Attest:

KARL Ha AXLINE ROBERT C. WATSON Attesting Oflicer Commissioner ofPatents

1. A WATER-INSOLUBLE DIALKYL MONOCHLOROMETHANEPHOSPHONATE OF THE FORMULA